The Global System for Mobile Communication (GSM) is a standard for digital wireless communications with services, such as voice telephony. GSM, together with other technologies, is part of an evolution including e.g. General Packet Radio System (GPRS), and Universal Mobile Telecommunications Service (UMTS). UMTS is the next (3rd) generation mobile communication system, which provides an enhanced range of multimedia services, such as video.
In mobile networks people can be contacted by calling to their mobile telephone number or by sending to that number a so called short message by e.g. making use of the Short Message Service (SMS). The point-to-point Short message service (SMS) provides a way of sending messages of limited size to and from GSM mobiles. Detailed information can be found in the ETSI standard GSM 03.40 Version 5.3.0.
The Subscriber Identity Module (SIM) inside GSM phones was originally designed as a secure way to connect individual subscribers to the network but is nowadays becoming a standardized and secure application platform for GSM and next generation networks.
The SIM card is a smart card that saves subscriber information about identity, subscription, subscription environment, radio environment and other information. The information in the SIM is stored in a logical structure of files, one of which contains the so called “phone book”.
UMTS has specified the use of the USIM (universal SIM) as the evolution of SIM. In GSM and UMTS networks, the (U)SIM card is central both for subscriber identification and for providing value added services to users. Usually referred to as a SIM card, the USIM (UMTS Subscriber Identity Module) is the user subscription to the UMTS mobile network. The USIM contains relevant information that enables access onto the subscribed operator's network.
The development of GSM Networks and terminals to support more advanced data bearer technologies has allowed for the introduction of new exciting data services, such as communications, financial management, information retrieval, entertainment and game playing. Therefore the U(SIM) cards have a lot of subscriber specific information stored.
The Mobile Station (MS), also referred to as the “device”, represents the only equipment the GSM user ever sees from the whole system. It actually consists of two distinct entities. The actual hardware is the Mobile Equipment (ME), also referred to as the “terminal” or the “handset”, which consists of the physical equipment, such as the radio transceiver, display and digital signal processors. The subscriber information is stored in the Subscriber Identity Module (SIM), implemented as a Smart Card.
The mobile equipment is uniquely identified by the International Mobile Equipment Identity (IMEI) being a unique code that corresponds to a specific GSM handset. The SIM card contains the International Mobile Subscriber Identity (IMSI), identifying the subscriber, a secret key for authentication, and other user information.
The IMEI and the IMSI are, however, independent and can thereby provide personal mobility.
The central component of the network subsystem is the mobile services switching center. This acts like a normal switching node of the PSTN (Public Switched Telephone Network) or ISDN (Integrated Services Digital Network) and connects the mobile signal to these fixed networks. It additionally provides all the functionality needed to handle a mobile subscriber, such as registration, authentication, location updating, handovers and call routing to a roaming subscriber. The Mobile Station Integrated Service Digital Network Number, MSISDN, is the standard international telephone number used to identify a given subscriber.
The operator declares the subscription in a database inside the network, which holds the correspondence between the IMSI and the MSISDN. By inserting the SIM card into another GSM terminal, the user is able to receive and make calls from that terminal, and receive other subscribed services.
When a new (U)SIM is issued, a lot of information, both personal and to some extent operator defined, is lost, unless this information is copied from the old (U)SIM to the new (U)SIM. This could for example be the phone book.
Introducing a new terminal has other, problems—since it is not personalized as (U)SIM cards are. Hence it is required to be configured with network settings to be enabled to use the different services the Mobile Service Provider offers. Apart from that, the same problem with personal information and services, as with the (U)SIM Cards, applies.
Some problems arise when an end user wants to change either subscription or terminal or both as data stored in the old terminal and/or old (U)SIM card can get lost.
Some SIM or mobile terminal specific solutions to handle this problem exist, but they do not combine both. For example, due to competitive reasons, mobile terminal suppliers develop products for managing their own terminals, but do not support terminals provided by other vendors.